Briefly about relational databases

Almost all databases have the following components

1. Types of data

2. operations and management structure

3. CRUD data operations

4. Relational tables, single. Data Normalization, Normal Forms

5. Types of requests.

5.1 subqueries

5.2 compound requests

5.3 Joun combines 8 types

5.4 Union

6. types of keys (limiting, key) their behavior

7. selection with aggregation and grouping

7.1 simple sampling, limitations

7.2 full aggregation

7.3 Group Aggregation

7.4 aggregate for external and internal conditions

7.5 sweep aggregation examples, purpose

8. stored functions, procedures, temporary tables, views, cursors

9. types of triggers

10 transactions, ACID, isolation levels